[PATCH 0/6] Miscellaneous FWU fixes

[Sughosh Ganu]

On Wed, 4 Sept 2024 at 17:30, Michal Simek <michal.simek at amd.com> wrote:
>
>
>
> On 8/30/24 13:40, Sughosh Ganu wrote:
> >
> > The following set of patches are miscellaneous fixes and some
> > hardening of the FWU update logic.
> >
> > Sughosh Ganu (6):
> >    fwu: v2: perform some checks before reading metadata
> >    fwu: v2: try reading both copies of metadata
> >    fwu: v1: do a version check for the metadata
> >    fwu: check all images for transitioning out of Trial State
> >    fwu: add dependency checks for selecting FWU metadata version
> >    fwu: do not allow capsule processing on exceeding Trial Counter
> >      threshold
> >
> >   include/fwu.h            | 11 ++++++
> >   lib/fwu_updates/Kconfig  |  1 +
> >   lib/fwu_updates/fwu.c    | 31 +++++++++++++++-
> >   lib/fwu_updates/fwu_v1.c | 18 +++++++--
> >   lib/fwu_updates/fwu_v2.c | 80 ++++++++++++++++++++++------------------
> >   5 files changed, 99 insertions(+), 42 deletions(-)
> >
>
> I found one more thing.
>
> I did this change
>
> diff --git a/tools/mkfwumdata.c b/tools/mkfwumdata.c
> index fbc2067bc12d..dab9530e499c 100644
> --- a/tools/mkfwumdata.c
> +++ b/tools/mkfwumdata.c
> @@ -293,7 +293,7 @@ static void fwu_fill_version_specific_mdata(struct
> fwu_mdata_object *mobj)
>          struct fwu_mdata *mdata = mobj->mdata;
>
>          mdata->metadata_size = mobj->size;
> -       mdata->desc_offset = sizeof(struct fwu_mdata);
> +       mdata->desc_offset = 0x21; sizeof(struct fwu_mdata);
>
>          for (i = 0; i < MAX_BANKS_V2; i++)
>                  mdata->bank_state[i] = i < mobj->banks ?
>
>
> to break desc_offset location. I generated mdata structure and write it to
> primary mdata partition.
>
> This has been spotted by (my debug) which is the reason why I did it.
>
>         if (g_mdata.desc_offset != FWU_IMG_DESC_OFFSET) {
>                 printf("mdata offset is not 0x20\n");
>                 return false;
>         }
>
> But I got one more message below which
>
> mdata offset is not 0x20
> Both FWU metadata copies are valid but do not match. Restoring the secondary
> partition from the primary

The reason why this logic is in place is to handle the scenario
whereby, during the metadata update, the primary copy gets updated
correctly, but due to some reason (like a power cut), the secondary
copy does not -- this is because the primary copy gets updated first.
In such a scenario, the secondary copy of metadata can be then
restored from the primary copy. In the scenario where the primary copy
is corrupted, it will show up in the crc check, and will get restored
from the secondary copy.

-sughosh

>
> But this is wrong. 0x21 there is wrong as been detected but sync code detects it
> as correct one and by this break also backup copy.
>
> Thanks,
> Michal